Strip feeders of widely varying construction and capabilities are old and well known in the material handling art. They find particularly advantageous application as feeders for punch presses. It is conventional with a punch press, for example, for such a feeder to intermittently advance a metal strip for a predetermined distance through the press. Between each feed cycle, while the strip is stationary, the press is effective to perform a working operation on the strip, i.e., punch out an electrical terminal, for example.
Feeders are conventionally driven by a press in timed relationship to its punching operation. Early strip feeders employed clutches and brakes to control the feed. Direct drive feeders were then developed which eliminated clutches and brakes in favor of cam mechanisms, such as illustrated in the Portmann U.S. Pat. No. 3,784,075, or index mechanisms, such as illustrated in Eyeberger U.S. Pat. No. 3,483,782, for example.
These strip feeders conventionally provided for adjustment of the length of strip fed in each feed cycle. In the Eyeberger patent construction, for example, the feed length is adjusted by changing the size of the idler sprocket 30.
With known feeders the feeder and the punch press must be shut down while the feed length is changed. The feed length adjustment process is time consuming and costly in terms of lost production. With feeders such as illustrated in the Eyeberger patent a different sprocket arrangement must be inventoried for each feed length desired.